A multiple access mobile communication system enables mobile terminals to perform radio communication substantially simultaneously, by sharing radio resources including at least one of time, frequency, and transmission power among the mobile terminals. Typical examples of multiple access schemes include a Time Division Multiple Access (TDMA), a Frequency Division Multiple Access (FDMA), a Code Division Multiple Access (CDMA), an Orthogonal Frequency Division Multiple Access (OFDMA), and any combination thereof. Unless otherwise stated, the term “mobile communication system” used in this specification means a multiple access mobile communication system.
A mobile communication system includes at least one mobile terminal and a network. The network includes a radio access network (RAN) and a core network (Mobile Core Network (CN)). The mobile terminal communicates with an external network (e.g., the Internet, packet data network, or Public Switched Telephone Networks (PSTN)) through the RAN and the CN. The mobile communication system is, for example, a Universal Mobile Telecommunications System (UMTS) or an Evolved Packet System (EPS) of the 3rd Generation Partnership Project (3GPP). The RAN is, for example, a Universal Terrestrial Radio Access Network (UTRAN) or an Evolved UTRAN (E-UTRAN). The CN is, for example, a General Packet Radio Service (GPRS) packet core or an Evolved Packet Core (EPC).
In the mobile communication system, in general, it is required to create a data bearer to transfer user packets between the external network and the mobile terminal per mobile terminal basis. This is because it is required to promptly switch and relocate a packet transfer route to provide mobile terminals with mobility. The data bearer is, for example, a UMTS bearer (General Packet Radio Service (GPRS) bearer), or an EPS bearer. The data bearer includes a radio access bearer (hereinafter referred to as a RAB) that is set in the RAN and a core network bearer (hereinafter referred to as a CNB) that is set in the CN.
The CNB is a tunnel that is set between a transfer node and an external gateway arranged in the CN, or a logical transmission path. The external gateway is a gateway node that is arranged in a boundary with the external network. The transfer node is a node that is arranged in a boundary with the RAN. The CNB is, for example, a CNB of the UMTS (i.e., GPRS Tunneling Protocol (GTP) tunnel), or an S5/S8 bearer of the EPS (i.e., GTP tunnel). Further, the external gateway is, for example, a Gateway GPRS Support Node (GGSN) or a Packet Data Network Gateway (P-GW). The transfer node is, for example, a user plane function of a Serving GPRS Support Node (SGSN) or a Serving Gateway (S-GW).
The RAB is a bearer between the mobile terminal and the transfer node of the CN. The RAB includes a radio bearer and a bearer between the RAN and the CN. The bearer between the RAN and the CN is set between a transfer node of the CN and a RAN node that performs a Radio Link Control (RLC) and a Radio Resource Control (RRC). The radio bearer is set between the mobile terminal and the RAN node described above in the RAN. The RAN node that performs the RLC and the RRC is, for example, a Radio Network Controller (RNC) of the UMTS or a base station (evolved NodeB (eNB)) of the EPS. The bearer set between the RAN and the CN is, for example, an Iu bearer (i.e., GTP tunnel) of the UMTS or an S1 bearer (i.e., GTP tunnel) of the EPS. The radio bearer is, for example, a Uu bearer of the UMTS or an LTE-Uu bearer of the EPS.
In summary, the CN need to create the CNB for each mobile terminal. The transfer node needs to store and manage a tunnel configuration regarding the CNB including a tunnel identifier (tunnel endpoint identifier) and an address of the external gateway (e.g., Internet Protocol (IP) address). The external gateway allocates a mobile terminal that attaches to the CN an address (e.g., IP address) to communicate with an external network, and performs, for the CNB, tunnel set up, charging control, and Quality of Service (QoS) control and the like.
For example, Non-patent literature 1 discloses procedures for establishing and recovering a data bearer (i.e., EPS bearer) to transfer user packets of a mobile terminal in response to an attach of the mobile terminal to a CN, a service request or the like in the EPS.